jerry commits (deposits) the changes and he wants to correct them for his recent commits. in this case, the function git commit -a will help do this. this function changes the last commit including your commit message; it creates a new commit id.
jerry modifies the previous commits using the git commit -a operation (signing changes) and he is ready to push the changes. push operation saves permanent data to git repository. after a successful push operation, other programmers can observe jerry's changes.
tom performs the simulation operation and sees a new file string.c. he wants to know who added this file to the repository and for what purpose, so he runs the git log command.
suppose you are implementing a new feature of your product. your code is in progress, suddenly a visitor. because of this, you have to go out for a few hours. you cannot commit this code and cannot throw it away at your changes. so you need some temporary space, where you can keep these local changes and then return to commit it.
github is a social network for programmers for software development projects using git revision management system. it also has a standard gui application for direct download (windows, mac, gnu / linux) to your computer from web sites. but in this tutorial, we only consider the cli section.
so far, both tom and jerry are using manual commands to compile their projects. now, jerry decided to create a makefile for the project and also put a name for the file string.c.